214 research outputs found

    Moving loads on railway bridges: The Spanish Code approach

    Full text link
    This paper presents the results of part of the research carried out by a committee in charge of the elaboration of the new Spanish Code of Actions in Railway Bridges. Following the work developed by the European Rail Research Institute (ERRI), the dynamic effects caused by the Spanish high-speed train TALGO have been studied and compared with other European trains. A simplified envelope of the impact coefficient is also presented. Finally, the train-bridge interactions has been analysed and the results compared with those obtained from simple models based on moving loads

    Magnetic Materials by Melt Spinning Method, Structural Characterization, and Numerical Modeling

    Get PDF
    Chill block melt spinning is used in industrial processes for the production of metallic glasses. It is a rapid solidification process whereby a liquid metal is ejected at high pressure and temperature via a nozzle onto a rotating wheel solidifying in the form of a ribbon. In this work, starting from an alloy with the composition of Fe78Si9B13 (% at.) reproduces the melt spinning technique to get the amorphous magnetic material. A CFD3D model based on the finite volume method (FVM) is proposed. For this purpose, the OpenFoam® open source code is used. In the ribbon production stage, it has been observed that the turbulence involved in the first reported transient lasts a few milliseconds, enough time to study the process with high-speed cameras. We measure the ejection speed by using optical flow on the melt contour. This enables us to check defects in the ribbons, which are predicted with the computational model, such as the case of cracks caused by irregularities in the first formation of the solid layer. The temperature measurement method relies on the fact that the digital camera is sensitive to electromagnetic radiation between 400 and 1000 nm in wavelength and the fact that the image gray level, which is proportional to the temperature T, provided the background illumination level is negligible

    Ice Dynamics and Morphological Changes During Proglacial Lake Development at Exploradores Glacier, Patagonia

    Get PDF
    Proglacial lakes are ubiquitous features formed during deglaciarization and are currently increasing in number in Patagonia and elsewhere. Proglacial lakes can affect glacier dynamics, catchment hydrology and have the potential to cause glacial lake outburst floods. Therefore, monitoring the onset and development of proglacial lake formation is relevant to understand glacial processes and anticipate glacier response to climate change. In this study, we integrate geomorphological and ice-dynamic information to assess proglacial lake development in Exploradores Glacier, Chilean Patagonia. We monitor recent spatial and temporal changes in the lower trunk of Exploradores Glacier (10 km2) to provide a 20-year observation record by combining eight uncrewed aerial vehicles (UAV) surveys between 2019 and 2020, with high-medium resolution satellite imagery (Rapid Eye and Landsat) between 2000 and 2018. We use feature tracking techniques, digital surface elevation model analysis and field data to create a multi-temporal scale (inter-annual and seasonal) and a multi-spatial (cm to km) data set. Our analysis shows that surface velocity overall trend has not changed over the last 20 years and that surface velocity near the terminus is significant (>10 m a−1). Moreover, an exceptional advance over moraine deposits was detected. We also found low downwasting rates (<0.5 m a−1) close to the glacier terminus which are attributed to sufficient ice flux and the insulation effect of the debris-covered surface. However, hundreds of supraglacial ponds were observed and are currently coalescing and expanding by ice-cliff backwasting favoring glacier disintegration. Lastly, it was found that calving losses at the east marginal lake equaled ice-flux input into the lake for the UAV monitored period. This study contributes to a better understanding of glacial lake dynamics during proglacial lake development, and our results may help ice modelling efforts to predict glacier response to future climate scenarios

    Algunas características léxicas del habla del panameño.

    Get PDF
    Mediante esta recopilación de antecedentes y opiniones acerca de algunas características léxicas presentes en el habla del panameño podemos vislumbrar una posible base de datos informativos. Presentamos los antecedentes de la historia del español en Panamá, comparado con el de los países de Latinoamérica, sin dejar de lado las normas generales para hablar el español. No debemos olvidar la trascendencia que tuvo el Canal de Panamá como paso de tasas naciones por nuestro país, sin dejar de lado la influencia del inglés. Se aponen las características a nivel léxico sobresalientes en nuestra habla, tomando en cuenta las variantes dialectales existentes. Concluimos con una serie de recomendaciones que deben ser abordadas para procurar un mejor uso del español que se habla de manera general en nuestro país

    Túneles urbanos con ventilación longitudinal y trampillas de extracción de humos

    Get PDF
    La ventilacion de tuneles urbanos presenta algunos problemas singulares especialmente en lo relativo a la evacuacion de humos provocados por un incendio. Generalmente la solucion adoptada es semi-transversal con trampillas de extraccion. Sin embargo en ciertas circunstancias puede ser preciso combinar estas con un sistema longitudinal basado en aceleradores. En este articulo se presenta la primera realizacion de este tipo proyectada en Espana y se describe el sistema de calculo. Se han preparado programas de calculo que permiten el estudio del acoplamiento de la accion de los ventiladores y el trafico. El modelo de trafico utilizado es macroscopico y corresponde a las curvas clasica que relacionan la intensidad, densidad y velocidad. Se extraen conclusiones relativas a la filosofia de actuacion en caso de incendio. Se muestran ecuaciones utilizadas y los graficos con los resultados obtenidos

    Investigation of the mechanism of chromium removal in (3-aminopropyl)trimethoxysilane functionalized mesoporous silica

    Get PDF
    We are proposed that a possible mechanism for Cr(VI) removal by functionalized mesoporous silica. Mesoporous silica was functionalized with (3-aminopropyl)trimethoxysilane (APTMS) using the post-synthesis grafting method. The synthesized materials were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), N-2 adsorption-desorption analysis, Fourier-transform infrared (FT-IR), thermogravimetric analyses (TGA), and X-ray photoelectron spectroscopy (XPS) to confirm the pore structure and functionalization of amine groups, and were subsequently used as adsorbents for the removal of Cr(VI) from aqueous solution. As the concentration of APTMS increases from 0.01 M to 0.25 M, the surface area of mesoporous silica decreases from 857.9 m(2)/g to 402.6 m(2)/g. In contrast, Cr(VI) uptake increases from 36.95 mg/g to 83.50 mg/g. This indicates that the enhanced Cr(VI) removal was primarily due to the activity of functional groups. It is thought that the optimum concentration of APTMS for functionalization is approximately 0.05 M. According to XPS data, NH3+ and protonated NH2 from APTMS adsorbed anionic Cr(VI) by electrostatic interaction and changed the solution pH. Equilibrium data are well fitted by Temkin and Sips isotherms. This research shows promising results for the application of amino functionalized mesoporous silica as an adsorbent to removal Cr(VI) from aqueous solution

    Interaction of Mesoporous Silica Nanoparticles with Human Red Blood Cell Membranes: Size and Surface Effects

    Get PDF
    The interactions of mesoporous silica nanoparticles (MSNs) of different particle sizes and surface properties with human red blood cell (RBC) membranes were investigated by membrane filtration, flow cytometry, and various microscopic techniques. Small MCM-41-type MSNs (∼100 nm) were found to adsorb to the surface of RBCs without disturbing the membrane or morphology. In contrast, adsorption of large SBA-15-type MSNs (∼600 nm) to RBCs induced a strong local membrane deformation leading to spiculation of RBCs, internalization of the particles, and eventual hemolysis. In addition, the relationship between the degree of MSN surface functionalization and the degree of its interaction with RBC, as well as the effect of RBC−MSN interaction on cellular deformability, were investigated. The results presented here provide a better understanding of the mechanisms of RBC−MSN interaction and the hemolytic activity of MSNs and will assist in the rational design of hemocompatible MSNs for intravenous drug delivery and in vivo imaging

    The Spanish Mediterranean Fishing Guilds (Cofradias): An Example of Collaborative Management with a Key Role in Sustainable Fisheries

    Full text link
    [EN] The management of Spanish coastal fisheries is based on a mixed model where the centralised action of the government is combined with the self-organisation of fishers in cofradias (guilds). These institutions have economic and political functions, intermediating between the State and the fishing sector and mediating in the conflicts that may occur. They also have welfare and mutualist tasks. This original and traditional co-management model is part of the social capital of traditional Spanish fishing. The aim of this article is to explore the possibilities of these Spanish fishers' organisations in order to improve the legitimacy of the fishery system and the sustainability of fisheries. Our hypothesis is that updating and adapting some aspects of the cofradias model could produce efficient forms of collaborative management and lead to improvements in the sustainability of fisheries. To validate this hypothesis the study analysed 69 face-to-face interviews in 21 Spanish-Mediterranean guilds. The analysis focused on three core aspects: the control of fishing resources; the integration of fishing knowledge in the management system; and, finally, the guilds contribution to the legitimacy of the system in the eyes of the fishers.This work was supported by National Plan for Scientific and Technological Research and Innovation (Spanish Economy and Competitiveness Ministry). Research Project CSO2016-76135-P. There is no conflict of interest declared in this article.Herrera-Racionero, P.; Lizcano, E.; Miret Pastor, LG.; Mascarell, Y. (2019). The Spanish Mediterranean Fishing Guilds (Cofradias): An Example of Collaborative Management with a Key Role in Sustainable Fisheries. Fisheries. 44(4):172-182. https://doi.org/10.1002/fsh.10224S172182444Alegret J. L.1999.Gestión comunitaria cogestión y mercado. La evolución histórica de la gestión de la pesca en el Mediterráneo español. Pages109–124inG.Allut andJ.Pascual editors. Antropología de la pesca/Santiago de Compostela: Asociación Galega de Antropoloxía.La pesca a la Mediterrània 2016 Universidad de Alicante Alicante J. L Alegret J. L. Sánchez Lizaso Les confraries de pescadors a Espanya 47 54Andalusian Decree 86/2004 of March 2 2004 about Fishers Guilds and their Institutions. Available:https://www.juntadeandalucia.es/boja/2004/52/3Ariza, E., Pons, F., & Breton, F. (2016). Is «socio-ecological culture» really being taken into account to manage conflicts in the coastal zone? Inputs from Spanish Mediterranean beaches. Ocean & Coastal Management, 134, 183-193. doi:10.1016/j.ocecoaman.2016.10.006Catalan Law 22/2002 of July 12 2002 of Fishers Guilds. «DOGC» n. 3684. Available:https://www.boe.es/buscar/pdf/2002/BOE-A-2002-15890-consolidado.pdfCochrane, K. L., & Garcia, S. M. (Eds.). (2009). A Fishery Manager’s Guidebook. doi:10.1002/9781444316315Corral-Quintana, S., Legna-de la Nuez, D., Legna Verna, C., Hernández, J. H., & Romero-Manrique de Lara, D. (2016). How to improve strategic decision-making in complex systems when only qualitative information is available. Land Use Policy, 50, 83-101. doi:10.1016/j.landusepol.2015.09.0045. European Comission.2013.Commission implementing regulation6. (EU) Nº 1419/2013. Availablehttp://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32013R1419&from=ES(May2017)European Commission.2014.Coastal zones: achieving sustainable management. Availablehttp://ec.europa.eu/environment/integration/research/newsalert/pdf/coastal_zones_sustainable_management_46si_en.pdf(May 2017).European Parliament.2012.Common position on the role of the RACS in the future Common Fisheries Policy Reform. Available:http://www.europarl.europa.eu/document/activities/cont/201203/20120322ATT41696/20120322ATT41696EN.pdf(May 2017).Frangoudes, K., Marugán-Pintos, B., & Pascual-Fernández, J. J. (2008). From open access to co-governance and conservation: The case of women shellfish collectors in Galicia (Spain). Marine Policy, 32(2), 223-232. doi:10.1016/j.marpol.2007.09.007Herrera-Racionero, P., Lizcano-Fernández, E., & Miret-Pastor, L. (2015). «Us» and «them». Fishermen from Gandía and the loss of institutional legitimacy. Marine Policy, 54, 130-136. doi:10.1016/j.marpol.2014.12.018Jentoft, S. (2000). Legitimacy and disappointment in fisheries management. Marine Policy, 24(2), 141-148. doi:10.1016/s0308-597x(99)00025-1Kosamu, I. B. M. (2015). Conditions for sustainability of small-scale fisheries in developing countries. Fisheries Research, 161, 365-373. doi:10.1016/j.fishres.2014.09.002Law 2/2007 of March 12 2007 of Marine Fishery and Aquaculture of Murcia region. Available inhttps://www.boe.es/boe/dias/2008/07/21/pdfs/A31793-31815.pdf(November 2018)Long, R. D., Charles, A., & Stephenson, R. L. (2015). Key principles of marine ecosystem-based management. Marine Policy, 57, 53-60. doi:10.1016/j.marpol.2015.01.013Mackinson, S., Wilson, D. C., Galiay, P., & Deas, B. (2011). Engaging stakeholders in fisheries and marine research. Marine Policy, 35(1), 18-24. doi:10.1016/j.marpol.2010.07.003MAGRAMA (Ministry of Agriculture Food and Environment).2015.Estadísticas pesqueras: Pesca marítima. Availablehttp://www.magrama.gob.es/es/estadistica/temas/estadisticas-pesqueras/pesca-maritima/(July 2017)Martínez-Novo, R., Lizcano, E., Herrera-Racionero, P., & Miret-Pastor, L. (2016). Innovation or ‘Inventions’? The conflict between latent assumptions in marine aquaculture and local fishery. Public Understanding of Science, 27(2), 214-228. doi:10.1177/0963662516651358Noy, C. (2008). Sampling Knowledge: The Hermeneutics of Snowball Sampling in Qualitative Research. International Journal of Social Research Methodology, 11(4), 327-344. doi:10.1080/13645570701401305Ostrom, E. (2009). A General Framework for Analyzing Sustainability of Social-Ecological Systems. Science, 325(5939), 419-422. doi:10.1126/science.1172133Pita, P., Fernández-Vidal, D., García-Galdo, J., & Muíño, R. (2016). The use of the traditional ecological knowledge of fishermen, cost-effective tools and participatory models in artisanal fisheries: Towards the co-management of common octopus in Galicia (NW Spain). Fisheries Research, 178, 4-12. doi:10.1016/j.fishres.2015.07.021Producer organisations are officially recognised bodies set up by fishery or aquaculture producers. They play an essential role in running the European Common Fisheries Policy.State Marine Fishery Law: Law 3/2001 of March 26 2001. BOE (State Official Gazette) number 75. Available:https://www.boe.es/buscar/doc.php?id=BOE-A-2001-600
    corecore